The present invention relates to a solar heat collector system that generates heat-pump cycles by sequentially coupling a plurality of solar heat collectors comprised of a compressor, a condenser, an expansion valve, and an evaporator, for heating fluid such as water in the condensor by collecting heat from solar beams and the atmosphere for delivery to hot-water supply systems and/or indoor air-conditioners.
Any conventional solar heat collector system uses either water or air as heating media by causing such heating media to circulate through a heat collector installed on the roof of a building to absorb heat from sun beams, allowing the absorbed heat to be transferred into a heat pool using heat media in order to use heated air or water for the hot-water supply system or indoor air-conditioners. When operating such a system, since the temperature of the heating media passing through the solar heat collector becomes higher than the atmospheric temperature due to the function of the heating media, a conventional heat collector needs a variety of heat-insulation structures to minimize radiation of heat from the heating media when collecting the heat, and yet, such heat-insulation structures are expensive and heavy. In addition, since heat collected is only from solar beam radiation, the heat collection capacity of any conventional solar heat collector system varies significantly according to weather conditions. Thus, any such conventional solar heat collection system needs to provide an auxiliary heating source to compensate for the shortage of calories when sufficient heat from sunbeams can not be collected.
Recently, independent of these, a new type of solar heat collector system has also been developed, which generates heat-pump cycles by sequentially coupling a compressor using freon gas (chlorofluoro hydrocarbon) for the heating media, a condensor, an expansion valve and an evaporator. Since this system uses such a heat pump cycle by applying evaporation and condensation of heating media, by properly adjusting the temperature of the evaporated heating media inside the heat collector (evaporator), not only the solar heat, but atmospheric heat can also be absorbed, thus dispensing with insulation of the heat collector board and of the selective absorption film as well. In order to positively absorb atmospheric heat, it is desirable to expand the area of the heat collector board in contact with the atmosphere an provide a well-ventilated configuration. Such a new system eliminates glass, cases, insulation material or the vacuum process otherwise needed for conventional plain-board type heat collectors and vacuum glass tubes, thus drastically reducing the cost of heat collectors. In addition, since the total weight is greatly reduced, installation costs can be lowered. Such a new system also makes it possible to collect atmospheric heat in addition to solar heat, and it thus effectively collects heat even when the heat from sunbeams is extremely scarce, or during cloudy periods, without resorting to any auxiliary heating source, thus saving on costs otherwise needed for the installation of such auxiliary heating sources, and for fuel. Since the new system uses freon gas for its heating media, it dispenses with methods of preventing freezing and corrosion that unavoidably occurs in tubes during winter when using water for the heating media. FIG. 1 is a perspective view of the heat collector of this system and FIG. 2 a sectional view. A heat collector of this type is provided with a plurality of heat collectors (3) comprising the heating media tube (1) and a fin (2) these heat collectors (3) being installed in parallel to a pair of base plates (4). This system sequentially connects adjacent heating media tubes secured to the base (5) or a number of fins (7) secured at right angles to the heating media tube (6) which is installed in the form of a snake movement, as shown in FIG. 3. Nevertheless, when such a heat collector system featuring the above configuration is installed on the roof of a conventional house or other building, it may adversely affect the appearance of the building when compared to conventional plain-type heat collectors or heat collectors using a heat collector incorporating vacuum glass tubes. Likewise, when installing this heat collector system on a newly-built house, just as for conventional heat collectors, the owner needs to pay the price of the heat collectors together with the price of the roofing material. In contrast to a conventional heat-pumping air-conditioner using air or water as a heating source, the effectiveness of heat collectors (evaporators) of heat-pump type heat collector systems is variable being affected both by atmospheric or water temperature, as well as by the amount of sunbeam radiation. As a result, the variable range is extremely wide. In other words, when a sufficient amount of sunbeams can be collected and the atmospheric temperature rises, the heat collection capacity sharply increases. Conversely, the heat collection capacity significantly decreases when sufficient sunbeams cannot be received or atmospheric temperature is low. In many cases, the amount of sunbeams is widely and quickly variable, thus making it difficult to adequately control the cycle of the heat pump operation. Likewise, the load from hot-water supply systems and air-conditioning varies according to seasonal factors. In this case, the maximum load is required throughout the winter season, decreases during spring and autumn and is reduced to minimum levels during the summer season. In other words, as in the case of conventional heat collector systems, the heat collection capacity of a direct-expansion heat-pump system heat collector of this kind has inverse characteristics to those necessary, whereby its load capacity decreases during winter, when a greater load is required, and increases during the summer when the least load is required. In addition, since such a heat collector system rotates the compressor using the power for collecting heat by forming a heat-pumping cycle, compared to the pump input of conventional heat collector systems using water for the heating media, this system consumes a large amount of power. As a result, it not only absorbs heat from solar beams, but it also absorbs atmospheric temperature. Nevertheless, since a specific amount of power is constantly needed even during summer, or when sufficient sunbeams are available, compared to such conventional heat collector systems using water for the heating media, this system is obliged to consume a large amount of power even during summer, and when sufficient sunbeams are available, thus eventually resulting in quite uneconomical operation throughout its service life.